West Nile Virus (WNV) represents a significant threat to public health in the United States, particularly in vulnerable populations such as the elderly and the immunocompromised. This mosquito-borne pathogen has spread throughout North America to countries including Canada and Mexico as well as to Central America, South America, and the Caribbean. Although most WNV infections are either mild or asymptomatic, neuroinvasive disease is accompanied by a high mortality rate (up to 35% in the hospitalized elderly). Moreover, up to 77% of survivors who recover from acute WNV encephalitis endure long-term neurological sequelae resulting in problems such as impaired gait, muscle weakness, hearing loss, and tremors for more than or equal to 3 years after infection. WNV is an emerging infectious disease and is listed as an NIAID Category B Priority Pathogen. Although there is an effective veterinary vaccine against WNV, there are currently no FDA-approved vaccines available for preventing human WNV infection. In this proposal, we will use a proprietary new platform technology for developing an inactivated vaccine formulation that can be used to immunize a diverse population including immunologically vulnerable groups such as the elderly. Our preliminary studies demonstrate that this vaccine approach is feasible, highly immunogenic (eliciting CD8+ T cell and neutralizing antibody responses) and protects mice against lethal WNV infection. In this project, we will evaluate candidate vaccine formulations in two animal models, perform scale-up development and cGMP manufacturing of the lead candidate vaccine, and perform benchmark preclinical studies necessary for preparing an IND application and initiating future Phase I clinical trials.